[PATCH v2 0/3] Introduce CONFIG_MSHV_ROOT for root partition code
From: Nuno Das Neves
Date: Thu Feb 20 2025 - 13:33:59 EST
Running in the root partition is a unique and specialized case that
requires additional code. CONFIG_MSHV_ROOT allows Hyper-V guest kernels
to exclude this code, which is important since significant additional code
specific to the root partition is expected to be added over time.
To do this, change hv_root_partition to be a function which is stubbed out
to return false if CONFIG_MSHV_ROOT=n, and don't compile hv_proc.c at all,
stubbing out those functions with inline versions.
Store the partition type (guest or root) in an enum hv_current_partition_type,
which can be extended beyond just guest and root partition.
While at it, introduce hv_result_to_errno() to convert Hyper-V status codes
to regular linux errors. This is useful because the caller of a hypercall
helper function (such as those in hv_proc.c) usually can't and doesn't
interpret the Hyper-V status, so it is better to convert it to an error code
and reduce the possibility of misinterpreting it. This also alows the stubbed
versions of the hv_proc.c functions to just return a linux error code.
Signed-off-by: Nuno Das Neves <nunodasneves@xxxxxxxxxxxxxxxxxxx>
---
Changes in v2:
* Add patch to convert hypercall statuses to linux error codes [Easwar
Hariharan]
* While at it, split the original patch into two logical pieces, one to change
hv_root_partition into a function, and one to introduce MSHV_CONFIG_ROOT
* Improve the clarity of and add an error message to
hv_identify_partition_type() [Easwar Hariharan] [Michael Kelley]
* Better explain *why* the patches are useful, in the commit messages [Michael
Kelley]
* Add a Kconfig comment explaining why PAGE_SIZE_4KB is needed [Michael Kelley]
* Minor style and typo fixes
Nuno Das Neves (3):
hyperv: Convert hypercall statuses to linux error codes
hyperv: Change hv_root_partition into a function
hyperv: Add CONFIG_MSHV_ROOT to gate root partition support
arch/arm64/hyperv/mshyperv.c | 2 +
arch/x86/hyperv/hv_init.c | 10 ++---
arch/x86/kernel/cpu/mshyperv.c | 24 +----------
drivers/clocksource/hyperv_timer.c | 4 +-
drivers/hv/Kconfig | 16 +++++++
drivers/hv/Makefile | 3 +-
drivers/hv/hv.c | 10 ++---
drivers/hv/hv_common.c | 69 +++++++++++++++++++++++++++---
drivers/hv/hv_proc.c | 6 +--
drivers/hv/vmbus_drv.c | 2 +-
drivers/iommu/hyperv-iommu.c | 4 +-
include/asm-generic/mshyperv.h | 40 ++++++++++++++---
12 files changed, 137 insertions(+), 53 deletions(-)
--
2.34.1